/// <summary>
/// Internal use only
/// </summary>
protected HatinaryTree(BNode <T> hat, BNode <T> root)
{
Hat = hat;
Root = root;
}
/// <summary>
/// Construct a Binary Node, with data, left child and right child.
/// </summary>
/// <param name="data">
/// Nullable
/// </param>
/// <param name="l">
/// BNode of the same type. left child.
/// </param>
/// <param name="r">
/// BNode of the same type, right child.
/// </param>
public BNode(T data, BNode <T> l = null, BNode <T> r = null)
{
Data = data;
LeftChild = l;
RightChild = r;
}